Fabrication And Characterization of Zinc Oxide/Tungsten Oxide Bi-Layer Structure Gas Sensing

Rapid development over the last several decades has resulted in a marked rise in air pollution and a fall in air quality, which has caused a variety of respiratory ailments. Nowadays, the use of thin film gas sensors is growing in significance for the identification of hazardous chemicals. The thin film, whose thickness ranges in nm, is created using certain materials and processes that determine the sensor's sensitivity. In this specific field of research, the key area of research interest is the synthesis of materials that are capable of gas sensing. When compared to mono layer, the integration of two or more metal oxides to generate a hetero junction interface has been shown to be capable of demonstrating improved gas sensing performance in terms of responsiveness and selectivity. These metal semiconductor sensorsare fabricated by depositing a thin film on different materials using various methods namely, sol gel process, CVD, Hydrothermal and DC/RF Sputtering. In this proposed work, a resistive device based on compound semiconductor Zinc Oxide (ZnO) and bi layer structure based on Zinc Oxide/Tungsten Trioxide (ZnO/WO3) fabricated on a p-type silicon dioxide waferwith silver (Ag) as a metal contact. The fabricated layers were characterized by Scanning Electron Microscopy (SEM) X-ray diffraction (XRD) and EDAX, revealed a wurtzite crystalline structure of ZnO and IV Characteristics were obtained from fabricated device are in resistive nature. Furthermore, device is characterized for gas sensing application to sense the acetone, nitrogen with the help of Electrochemical analyzer indicating the improved sensitivity for bilayer structure formed by a factor of about 0.5uA to 14uA.